System and method to determine radio frequency identification (rfid) tags

Abstract

A system comprises a radio frequency identification (RFID) reader, a presence detector, and at least one processor operationally coupled to the RFID reader and the presence detector. The at least one processor determines, whether a RFID tag and a RFID tag read time are identified; determine, via the presence detector, a last movement time period; determines whether the RFID tag read time is within the last movement time period; determines whether the RFID tag is on a tag list and update the RFID tag to a tag list when the RFID tag read time is within or not within the last movement time period and RFID tag is on the tag list, or add the RFID tag to a stray list when the RFID tag read time is within or not within the last movement time period and the RFID tag is not on tag list.

What is claimed is: 
     
         1 . A system comprising:
 a radio frequency identification (RFID) reader;   a presence detector communicatively coupled with the RFID reader; and   at least one processor operationally coupled to the RFID reader and the presence detector, wherein the at least one processor is configured to:
 determine, via the RFID reader, whether a RFID tag and a RFID tag read time are identified; 
 determine, via the presence detector, a last movement time period associated with the RFID tag on identifying the RFID tag and the RFID tag read time; 
 determine whether the RFID tag read time is within the last movement time period associated with the RFID tag; 
 determine whether the RFID tag is on a tag list; and, 
 update, when the RFID tag read time is within the last movement time period associated with the RFID tag and the RFID tag is on the tag list, the tag list based at least on the RFID tag; or 
 add, when the RFID tag read time is within the last movement time period associated with the RFID tag and the RFID tag is not on the tag list, the RFID tag to the tag list; or 
 update, when the RFID tag read time is not within the last movement time period associated with the RFID tag and the RFID tag is on the tag list, the RFID tag to the tag list; or 
 add, when the RFID tag read time is not within the last movement time period associated with the RFID tag and the RFID tag is not on the tag list, the RFID tag to a stray list. 
   
     
     
         2 . The system of  claim 1 , wherein the last movement time period comprises a last read time of the RFID tag. 
     
     
         3 . The system of  claim 1  further comprises a plurality of reference RFID tags that are calibrated with the RFID reader, and wherein the at least one processor is further configured to determine radio frequency (RF) power at a channel associated with one of the plurality of RFID tags and to set a calibration time period. 
     
     
         4 . The system of  claim 3 , wherein the RFID reader is configured to read the RFID tag with the determined RF power at the channel to identify the RFID tag and the RFID tag read time. 
     
     
         5 . The system of  claim 4 , wherein when the RFID tag read time is not identified, the at least one processor is further configured to determine whether dwell time period is expired, wherein the dwell time period corresponds to a time period for reading the RFID tag by the RFID reader. 
     
     
         6 . The system of  claim 5 , wherein upon determining the dwell time period expired, the at least one processor is further configured to switch the RFID reader on to another channel and reset the dwell time period, and upon determining the dwell time period not expired, the RFID reader is further configured to read the RFID tag with the determined radio frequency (RF) power at the channel. 
     
     
         7 . The system of  claim 3 , wherein the channel comprises at least one of an ultra-high frequency (UHF) channel, a low frequency (LF) channel, or a very high frequency (VHF) channel. 
     
     
         8 . The system of  claim 1 , wherein the presence detector comprises at least one of infrared (IR) sensor, millimeter (MM) wave sensor, microwave sensor, accelerometer, gyroscope, or radar sensor. 
     
     
         9 . The system of  claim 3 , wherein the at least one processor is further configured to determine whether the calibration time period is expired, wherein upon determining the calibration time period expired, the at least one processor is further configured to re-calibrate the RFID reader to determine radio frequency (RF) power. 
     
     
         10 . The system of  claim 3 , wherein upon determining the calibration time period not expired, the RFID reader is configured to read another RFID tag with the determined RF power at the channel. 
     
     
         11 . A method comprising:
 determining, via a RFID reader, whether a RFID tag and a RFID tag read time are identified;   determining, via a presence detector, a last movement time period associated with the RFID tag on identifying the RFID tag and the RFID tag read time;   determining, via at least one processor, whether the RFID tag read time is within the last movement time period of the RFID tag;   determining, via the at least one processor, whether the RFID tag is on a tag list; and,   updating, via the at least one processor, when the RFID tag read time is within the last movement time period of the RFID tag and the RFID tag is on the tag list, the tag list based at least on the RFID tag, or   adding, via the at least one processor, when the RFID tag read time is within the last movement time period of the RFID tag and the RFID tag is not on the tag list, the RFID tag to the tag list, or   updating, via the at least one processor, when the RFID tag read time is not within the last movement time period of the RFID tag and the RFID tag is on the tag list, the RFID tag to the tag list, or   adding, via the least one processor, when the RFID tag read time is not within the last movement time period of the RFID tag and the RFID tag is not on the tag list, the RFID tag to a stray list.   
     
     
         12 . The method of  claim 11 , wherein the last movement time period comprising a last read time of the RFID tag. 
     
     
         13 . The method of  claim 11  further comprising calibrating the RFID reader with a plurality of reference RFID tags. 
     
     
         14 . The method of  claim 13  further comprising determining radio frequency (RF) power at a channel associated with one of the plurality of RFID tags and setting a calibration time period. 
     
     
         15 . The method of  claim 14  further comprising reading, via the RFID reader, the RFID tag with the determined RF power at the channel to identify the RFID tag and the RFID tag read time. 
     
     
         16 . The method of  claim 15  further comprising determining whether dwell time period is expired upon determining the RFID tag read time is not identified, wherein the dwell time period corresponds to a time period for reading the RFID tag by the RFID reader. 
     
     
         17 . The method of  claim 16  further comprising switching the RFID reader on to another channel and resetting the dwell time period upon determining the dwell time period expired, and reading the RFID tag with the determined radio frequency (RF) power at the channel upon determining the dwell time period not expired. 
     
     
         18 . The method of  claim 14 , wherein the channel comprises at least one of an ultra-high frequency (UHF) channel, a low frequency (LF) channel, or a very high frequency (VHF) channel, and wherein the presence detector comprises at least one of infra-red (IR) sensor, millimeter (MM) wave sensor, microwave sensor, accelerometer, gyroscope, or radar sensor. 
     
     
         19 . The method of  claim 14  further comprising determining whether the calibration time period is expired, wherein upon determining the calibration time period expired, re-calibrating, via the one or more processors, the RFID reader to determine radio frequency (RF) power. 
     
     
         20 . The method of  claim 14  further comprising reading another RFID tag with the determined RF power at the channel upon determining the calibration time period not expired.